Tevez, who is presently on international duty at the Copa America, has made no secret of his desire to move to Old Trafford.

And a conclusion to his protracted transfer looked to move a step closer when his representatives claimed a medical had been set up.

But a West Ham spokesman responded: "He remains contracted to and registered with West Ham and there is no change to that situation.

"Obviously, a move cannot take place without the agreement of West Ham and the Premier League."

Manchester United have already agreed terms with the player, but while West Ham hold Tevez's registration, his economic rights are owned by his representative Kia Joorabchian.

And the deal stalled after the Premier League insisted West Ham had to receive the majority share of any transfer fee.

We think he is our player and are very hopeful

Man Utd's Sir Alex Ferguson

However, sources close to Joorabchian are confident they are on sound legal footing to go ahead with the transfer.

And Ferguson still believes Tevez is bound for Old Trafford.

"I think we have got the player. We think he is our player and are very hopeful," said the Scot.

"The Premier League seem to be holding back, I think they probably want to make sure everything is transparent.

"We want that to be the case. We don't want a bad taste surrounding the transfer, we want it done cleanly."

I suspect what will happen is that Tevez will tell Fifa that he doesn't want to go back to West Ham

BBC sports editor Mihir Bose

The confusion was created last season when West Ham failed to inform the Premier League they had entered into an agreement with Joorabchian's company MSI when they signed Tevez and fellow Argentine Javier Mascherano.

The Hammers were fined £5.5m and warned that Tevez would be unable to play for them while the third-party agreement was still in place.

West Ham immediately ripped it up - but Joorabchian claims he did not agree to that.

However, the Premier League is now insisting that Tevez's transfer must only involve West Ham and Manchester United.

And BBC sports editor Mihir Bose reports that West Ham face action if they do not "assert their rights" over Tevez.

Bose said: "There are voices being raised in football who are not all happy about the Premier League's role in the transfer.

"They feel the Premier League, which is owned by the clubs, is exceeding its regulatory powers and accuse it of using bully-boy tactics to force West Ham to toe the line.

"The Premier League vehemently rejects this charge. It says West Ham told them they had torn up the agreement with MSI and had complete control over Carlos Tevez, there was no third party influence of the player.

"The Premier League merely wants West Ham to stick to this agreement and prove the undertakings they gave the Premier League still hold."

Bose added: "The terms are he will go on a two-year loan and that a loan fee will be paid to Joorabchian's company of about £10m.

"The player himself will get about £4.5m a year and Manchester United could buy the player but would probably have to pay another £30m.

"I suspect what will happen is that Tevez will tell Fifa that he doesn't want to go back to West Ham and the world governing body will have to resolve whether a player can be forced to stay at a club."

It is understood Tevez's camp believe the Premier League can no longer act as independent arbiter in the case.

The Argentine and his representatives have written separate letters to both the League and West Ham to ask them to terminate the striker's Hammers contract - a request refused by both parties.

Fifa says it may be prepared to step in - but the matter would first have to go through the Football Association, which oversees domestic transfers.

A spokesman said: "Fifa considers the Tevez situation to be a domestic matter and therefore of the competence of the FA.

"If Fifa was to receive a formal request from any of the parties involved, it would look at the matter.

"However, the possibility exists that we would still determine that it is the FA who is competent to decide on the case."